1. Field of the Invention
The present invention relates to a recording medium having high gloss including metallic luster, an image-forming method employing the recording medium, and a printed matter obtained by the image-forming method.
2. Related Background Art
Ink-jet recording is a recording method which conducts recording through steps of forming ink droplets, ejecting the ink droplets, and depositing a part or the whole of the ejected ink onto a recording medium such as a paper sheet or a plastic film coated with an ink-receiving layer. The above ink droplets are formed by various methods such as electrostatic attraction, mechanical vibration or displacement by a piezo-electric element, pressure application by bubbling of ink by heating. The ink-jet recording method is attracting attention because of less noise generation, and capability of high speed printing and multi-color printing.
The ink for ink-jet recording system is mainly composed of water in view of safety, and recording characteristics. Frequently, a polyhydric alcohol is added to the ink to prevent clogging in a nozzle, and to improve ejection stability.
The recording medium for the ink-jet recording includes various kinds of paper sheets, OHP films, glossy paper sheets, glossy films, cloth, etc. The method of feeding of the recording medium has developed, and automatic sheet feeding is mainly employed in place of manual sheet feeding.
The recording mediums conventionally employed include recording sheets for an overhead projector (hereinafter referred to as "OHP") constituted of a polyester film having thereon a hydrophilic film composed of polyvinyl alcohol of saponification degree of 70 mole percent to 90 mole percent as disclosed in Japanese Patent Application Laid-Open No. 60-220750; recording paper sheets constituted of a base paper sheet having a coating layer containing fine powdery silica and water-soluble binder like polyvinyl alcohol as disclosed in Japanese Patent Publication No. 3-26665; glossy paper sheets constituted of an opaque base material like synthetic paper and having thereon a film mainly composed of a water-soluble resin; and so forth. Further, a cast-coated paper sheet for ink-jet recording having a coat layer formed by casting and mainly composed of silica and a binder is disclosed in Japanese Patent Application Laid-Open No. 63-265680.
As the results of improvements in performance of ink-jet recording apparatus such as a higher printing rate, and multi-color printing, more improvements are required for the ink-jet recording medium. The required properties for the ink-jet recording medium include: (1) higher ink absorbency (larger absorption capacity, and shorter absorption time); (2) capability of giving higher optical density of the printed ink dots without blurring at the dot periphery; (3) capability of giving nearly completely circular dots with smoothness of the dot periphery; (4) less change of properties caused by change of temperature and humidity without causing curling of the recording medium; (5) no occurrence of blocking; (6) capability of maintaining printed images stably for a long term (especially under high temperature and high humidity); and (7) stability of the recording medium itself over a long term without deterioration (especially under high temperature and high humidity). Various recording mediums are demanded with the increase of the printing speed, increase of the image density, development of color printing, and diversification of ink.
The ink-jet recording sheet disclosed in Japanese Patent Publication No. 3-26665 has a mat-like surface appearance without gloss. The glossy paper sheet disclosed in Japanese Patent Publication No. 5-36237 does not exhibit sufficient gloss at non-printed portions although it allows image formation with high gloss and high density in comparison with conventional paper.
Conventional recording mediums have had a specular gloss which tends to increase gradually with increase in specular glossiness when measuring it continuously with an angle of from 20.degree. to 75.degree., and to reach the maximum at 75.degree.. Therefore, the conventional recording mediums are not satisfactory in dynamic representation of color owing to poor contrast of gloss at a non-printed area, and sufficient gloss of the recording medium can be perceived only when the medium is viewed at an oblique angle since the specular glossiness has reached the maximum at 75.degree..
Conventional printed matters have had a specular gloss which tends to increase gradually with increase in specular glossiness when measuring it continuously with an angle of from 20.degree. to 75.degree., and to reach the maximum at 75.degree.. Therefore, the conventional printed matters are not satisfactory in dynamic representation of color owing to poor contrast of gloss at a non-printed area, and sufficient gloss of the printed matters can be perceived only when the medium is viewed at an oblique angle since the specular glossiness has reached the maximum at 75.degree..